COELACANTHIFORM CHARACTERISTICS:

      1) second dorsal, anal, pelvic, and pectoral fins lobe-like

      2) first dorsal fin with hollow spines

      3) caudal fin diphycercal and in three lobes

      4) double gular plate between left and right sides of lower jaw

      5) large, bony, cosmoid scales

      6) intracranial joint

      ILLUSTRATED SPECIMEN:

      Latimeria chalumnae, SIO 75–347, 950 mm TL

      CERATODONTIFORMES—Lungfishes

      DIVERSITY: 3 families, 3 genera, 6 species

      REPRESENTATIVE GENERA: Lepidosiren, Neoceratodus, Protopterus

      DISTRIBUTION: Sub-Saharan Africa (Protopterus), South America (Lepidosiren), and Australia (Neoceratodus)

      HABITAT: Freshwater; tropical to subtropical; benthic to demersal over soft bottoms

      REMARKS: The three families of living lungfishes, also called the Dipnoi, have one or two lungs used for either facultative or, in some cases, obligate air breathing (Graham, 1997). The African lungfishes (Protopteridae) are characterized by the presence of slender, elongate pectoral and pelvic fins, small scales, and six gill arches, while the montotypic South American Lungfish (Lepidosirenidae) also has slender pectoral and pelvic fins, small scales, and paired lungs, but only five gill arches. In contrast, the monotypic Australian Lungfish (Ceratodontidae) has paddle-like pectoral and pelvic fins, larger scales, and a single, unpaired lung. The African lungfishes are the sister group of the single species of South American Lungfish, and are placed together in the order Lepidosireniformes by some authors. These two lineages are the sister group of the single extant Australian Lungfish (Ceratodontidae). Nelson (2006) includes all three families in the order Ceratodontiformes. African lungfishes are large, with at least one species reaching lengths up to 1.8 m TL. During the dry season, individuals burrow into the mud and aestivate inside mucous cocoons. The pelvic fins of reproductive males of the South American Lungfish become highly vascularized and feather-like, infusing oxygen into the water where young are developing. Lungfishes are omnivorous, feeding on other fishes, frogs, mollusks, and in some cases, plant material, including seeds.

      REFERENCES: Bemis et al., 1987; Cloutier and Ahlberg, 1996; Graham, 1997; Nelson, 2006.

      CERATODONTIFORM CHARACTERISTICS:

      1) pectoral and pelvic fins slender (A and B) or flattened (C)

      2) gular plate absent

      3) premaxilla and maxilla absent

      4) one or two lungs

      5) five or six gill arches

      ILLUSTRATED SPECIMENS:

      A) Protopterus aethiopicus, CAS 46377, 854 mm TL (Protopteridae—African lungfishes)

      B) Lepidosiren paradoxa, CAS 14001–7, 549 mm TL (Lepidosirenidae—South American Lungfish)

      C) Neoceratodus forsteri, CAS 18189, 748 mm TL (Ceratodontidae—Australian Lungfish)

      ACTINOPTERYGII

      Ray-finned Fishes

      The Actinopterygii includes approximately 33,000 valid species (Eschmeyer and Fong, 2013) classified by Nelson (2006) in 453 families. They are found in all aquatic habitats occupied by vertebrates and range vastly in body size from a tiny species of the gobiiform genus Schindleria that grows no longer than 1 cm (and ca 0.7 mg) and spends its entire short life in the plankton, to the Oarfish (Regalecus) that grows to over 8 m in length, to the Ocean Sunfish (Mola mola) that weighs up to 2,300 kg. Given this enormous diversity, it is not surprising that the group is difficult to characterize morphologically. Extant actinopterygians have enlarged basal elements in the pectoral fins and fused basal elements in the pelvic fins (Lauder and Liem, 1983; Patterson, 1982). Early lineages (i.e., non-teleosts) have a single dorsal fin (variously lost or divided in many) and ganoid scales (variously lost or modified in most species). Several studies (e.g., Faircloth et al., 2013; Hurley et al., 2007; Inoue et al., 2003; Lauder and Liem, 1983) have examined the relationships among the major lineages of the Actinopterygii.

      

      Hypothesized phylogenetic relationships of the early lineages of actinopterygians (after Faircloth et al., 2013).

      Actinopterygii I

      Lower Ray-finned Fishes

      POLYPTERIFORMES : POLYPTERIDAE—Bichirs

      DIVERSITY: 1 family, 2 genera, 12 species

      REPRESENTATIVE GENERA: Erpetoichthys ( = Calamoichthys), Polypterus

      DISTRIBUTION: Africa

      HABITAT: Freshwater; tropical; demersal over soft bottoms

      REMARKS: Bichirs are thought to be the sister group of all other actinopterygians, exhibiting many unique characters. All bichirs have lungs, an intestinal spiral valve, a skeleton of mostly cartilage, and a uniquely divided dorsal fin. Pelvic fins are present in most species but absent in one (Erpetoichthys calabaricus). Bichirs are carnivorous and feed on other fishes, mollusks, and crustaceans. They are restricted to Africa, are known to reach lengths of up to 90 cm, and are often seen in the aquarium trade.

      REFERENCES: Britz and Johnson, 2003; Daget et al., 2001; Gayet et al., 2002; Gosse, 1984, 1988.

      POLYPTERIFORM CHARACTERISTICS:

      1) five to eighteen dorsal finlets, each with a single spine and one or more soft rays

      2) four gill arches

      3) spiracles large

      4) two gular plates

      5) branchiostegal rays absent

      6) ganoid scales

      7) maxilla fused to skull

      ILLUSTRATED SPECIMEN:

      Polypterus palmas, CU 87580, 126 mm TL

      ACIPENSERIFORMES—Sturgeons and Paddlefishes

      The sturgeons and paddlefishes are an ancient lineage of fishes that evolved in the Permian over 250 million years ago. They and the Polypteriformes have a complex mixture of traits not seen in other ray-finned fishes including a heterocercal tail, skeleton of mostly cartilage, and spiral valve in the intestine. In addition, the Acipenseriformes have a well-developed rostrum, lack an opercle, have a reduced or absent preopercle, and lack branchiostegal rays. The group includes two families, six genera, and 28 extant species. Living acipenseriforms are restricted to the Northern Hemisphere where they inhabit coastal areas and large river systems (Bemis et al., 1997).

      REFERENCES: Bemis et al., 1997; Chen and Arratia, 1994; Grande and Bemis, 1996

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